These are my Mizuno Enerzy. They are only a few years old, but they survived my 110kg to 75kg, 5km in 50 mins to 10km in 55 mins fitness journey. Its getting a bit embarrasing at the gym when people see the duct tape. Ive already stitched the holes up three times.
How long are running shoes supposed to last you? They are expensive! Are they expected to do this, or should they last much longer?
I have a pair of Altra Rivera 3 that have ~1500km. I am not sure there is any rule (except for marketing) saying you should change your shoes every x kms. I have a friend running ultras in >500km shoes because they are more comfortable and fit better.
IMO, you should change your shoes when they start to get uncomfortable